Page 2. Q1.Green plants can make glucose. Plants need energy to make glucose. How do plants get this energy? (2)

Transcription

1 Q1.Green plants can make glucose. (a) Plants need energy to make glucose. How do plants get this energy? (b) Plants can use the glucose they have made to supply them with energy. Give four other ways in which plants use the glucose they have made. (4) (Total 6 marks) Page 2

2 Q2. The diagram shows where three seaweeds live on a seashore. As the tide moves in and out, these seaweeds are covered with seawater for different lengths of time. Some students investigated the rate of photosynthesis in these seaweeds. They cut ten small discs from one seaweed. They dropped the discs into seawater in a beaker. They recorded the time taken for the fifth disc to float to the surface. They repeated this experiment with the other two seaweeds. (a) (i) Suggest why the discs floated to the surface. (ii) Suggest the advantage of recording the time taken for the fifth disc to reach the surface, rather than for the tenth disc. (b) The students carried out their experiments at different light intensities. The graph shows the results they collected. Page 3

3 (i) Compare the rate of photosynthesis for flat wrack with the rate for saw wrack at different light intensities. (ii) Seawater absorbs light. The growth rate of saw wrack is less than the growth rate of bladder wrack. Suggest why. (Total 6 marks) Page 4

4 Q3. Students investigated the effect of changing the carbon dioxide concentration on the rate of photosynthesis in pieces of leaf. Diagram 1 shows the type of leaf used by the students. The students: cut pieces of leaf from the green region put the pieces into tubes added different concentrations of carbon dioxide to each tube shone lights on the tubes with either high or low light intensity recorded the concentration of oxygen in the tubes after 5 hours. Diagram 2 shows how each experiment was set up. The graph shows the results of the investigation. Page 5

5 (a) (i) Describe the effect of increasing carbon dioxide concentration on the rate of photosynthesis at low light intensity. (ii) Explain the effect that you have described. In your answer you should refer to limiting factors. (b) What would have been the effect on oxygen concentration over the five-hour period if a white region of the leaf had been used, instead of a green region? Effect... Explain your answer. Explanation... Page 6

6 (c) Some people keep indoor plants which have variegated leaves (leaves with green and white regions). If plants with variegated leaves are kept in dim light conditions the white areas of the leaves start to turn green. This is an advantage to the plant. Suggest why. (Total 7 marks) Page 7

7 Q4. The graph shows the uptake of carbon dioxide and the release of carbon dioxide by a bean plant on a hot summer s day. (a) At which two times in the day did the rate of photosynthesis exactly match the rate of respiration in the bean plant? (b) The bean plant respires at the same rate all through the 24 hour period. (i) How much carbon dioxide is released each hour during respiration?... arbitrary units (ii) How much carbon dioxide is used by photosynthesis in the hour beginning at 3 pm? Page 8

8 Answer =... arbitrary units (c) Over the 24 hour period, the total amount of carbon dioxide taken in by the bean plant was greater than the total amount of carbon dioxide given out by the bean plant. Explain, in detail, why this was important for the bean plant. (Total 5 marks) Page 9

9 Q5. (a) Complete the equation for photosynthesis. lightenergy oxygen (b) Scientists investigated how temperature affects the rate of photosynthesis. The scientists grew some orange trees in a greenhouse. They used discs cut from the leaves of the young orange trees. The scientists used the rate of oxygen production by the leaf discs to show the rate of photosynthesis. (i) The leaf discs did not produce any oxygen in the dark. Why? (ii) The leaf discs took in oxygen in the dark. Explain why. (c) In their investigation, the scientists measured the rate of oxygen release by the leaf discs in the light. The scientists then measured the rate of oxygen uptake by the leaf discs in the dark. The graph shows the effect of temperature on oxygen production in the light oxygen production in the light added to oxygen uptake in the dark. Page 10

10 Use the information from the graph to answer each of the following questions. (i) Describe the effect of temperature on oxygen production in the light. (ii) Explain the effect of temperature on oxygen production in the light when the temperature is increased: from 25 C to 35 C from 40 C to 50 C. Page 11

11 (d) A farmer in the UK wants to grow orange trees in a greenhouse. He wants to sell the oranges he produces at a local market. He decides to heat the greenhouse to 35 C. Explain why he should not heat the greenhouse to a temperature higher than 35 C. Use information from the graph in your answer. (3) (Total 12 marks) Page 12

12 Q6.Some students studied bluebell plants growing in two different habitats. Habitat A was a sunny field next to woodland. Habitat B was a shady, moist woodland. A bluebell plant can have several flowers on one flower stalk. The students counted the number of flowers on each of 40 bluebell flower stalks growing in each habitat. The bar charts show the results. Habitat A: Sunny field next to woodland Number of flowers per stalk Habitat B: Shady, moist woodland Number of flowers per stalk (a) The students wanted to collect valid data. Describe how the students should have sampled the bluebell plants at each habitat to collect valid data. Page 13

13 (b) (i) The students used the bar charts to find the mode for the number of flowers per stalk in the two habitats. The mode for the number of flowers per stalk in habitat A was 11. What was the mode for the number of flowers per stalk in habitat B? Mode =... (ii) The students suggested the following hypothesis: The difference in the modes is due to the plants receiving different amounts of sunlight. Suggest why. (iii) Suggest how the students could test their hypothesis for the two habitats. (c) Suggest how receiving more sunlight could result in the plants producing more flowers per stalk. Page 14

14 (Total 9 marks) Q7.(a) Complete the equation for photosynthesis water (3) (b) The rate of photosynthesis in a plant depends on several factors in the environment. These factors include light intensity and the availability of water. Describe and explain the effects of two other factors that affect the rate of photosynthesis. You may include one or more sketch graphs in your answer. Page 15

15 (5) (Total 8 marks) Page 16